A manufacturing system for motor vehicle parts, for example for cylinder heads, is designed for a planned period of use of several years. Unplanned failures during the period of use give rise to considerable costs which under certain circumstances significantly exceed the costs of procuring the manufacturing system. For this reason, methods for being able to predict the frequency of unplanned failures, the down times and the costs resulting from the failures at an early time, for example when a manufacturing system is procured, are desired.
In VDI guideline VDI 2885, standard data for maintenance planning is defined and a procedure for determining maintenance costs is disclosed.
DE 19848094 A1 describes a method for predicting the effects of planned and random events on the availability of a technical system. A model of the technical system is required which reflects the interaction of components of the technical system. In particular, the model describes how the failure of one component affects the entire technical system. The time profile of the system availability is predicted using Monte-Carol simulations as a function of a maintenance strategy for the technical system.
Setting up such an availability model requires a large amount of expenditure and often cannot be carried out within an acceptable time for complex technical systems, for example manufacturing systems. To carry out the Monte-Carlo simulations it is necessary for statistical models for the unpredicted events and failure probabilities of all the components to be known as well as for a maintenance strategy to be predefined. These requirements are in fact often not met before, or at the start of, the use of manufacturing system.
EP 1160712 A2 discloses a device and a method for predicting the times of failures (“timing of a future service event”) of a technical system. Maintenance-related information, for example decomposition of the system and its components, failures and their repairs in the past as well as factors for the maintenance are required. The maintenance-related information is analyzed statistically in order to determine the components of reliability values, for example the times between failures. Furthermore, data relating to the performance of the system is acquired and performance losses during ongoing operation are determined using the information about failures and about the performance. Future failures are predicted by means of a simulation.
EP 1146468 A2 discloses a device and a method for predicting the times and costs of failures (“service event”) during the period of use of a technical system. The maintenance-related information which is known from EP 1160712 A2 is also required for this approach. Said information is analyzed statistically.
The approaches described in EP 1160712 A2 and EP 1146468 A2 require a simulation model for the times of future failures to be able to be predicted. Such a simulation model can often not be generated at all or not be generated with acceptable expenditure, in particular if the technical system is a complex dynamic one. Furthermore, the required characteristic values relating to the performance of the system are only available during ongoing operation if the components interact, but not before activation takes place.
DE 19751273 A1 describes a method for generating and handling a technical database which is available during the period of use of a technical system. Data relating to all the components of the technical system is collected in a uniform database at the earliest possible time, stored and updated. The database is managed using a uniform user interface. The database can be used, for example, for troubleshooting on the technical system as well as for training maintenance technicians.
DE 19751273 A1 describes the use of data relating to failures in the technical system for troubleshooting, but not the prediction of failure frequencies or down times. In the case of a complex technical system, the database can also become extensive and require a large amount of data which is not yet available at an early time of the period of use of the system.
WO 00/72212 A2 discloses a method and a device for determining the overall costs (“total cost of ownership”) of a complex system. The technical system is, for example, a production line. Information which relates to at least one aspect of the system, for example the function required by the system, is procured from an information system for various disciplines. Furthermore, information relating to the use of the system, for example the production planning with a production line as the technical system, is procured from the information system. The overall costs are determined from these two information items.
WO 01/26005 A1 discloses a method for analyzing the costs during the acquisition and operation of an IT system. The costs for acquisition and installation, for ongoing operating costs, for example for monitoring and fault recovery, and indirect costs, are differentiated. Depending on the characteristics of the IT system, on user profiles and on the operational organization, formal estimation methods (“appraisal metrics”) are applied, for example formulas which supply costs as a function of statistical characteristic values of an IT system and of the operator company. The results are compared with established reference values (“benchmarks”).
These methods require data which is not available with sufficient data quality before the system is procured. Furthermore, it is already impossible to carry out the methods for complex systems because they give rise to unwieldy models which are difficult to comprehend and verify.
US 2001/0023376 A1 discloses an information system for parts. A user enters a specification for parts into the information system. Types of parts which fulfill this specification are determined. For this purpose, the information system accesses various management systems, for example one for parts numbers, one for quality assurance, one for the management of stocks, one for the control of sales and marketing, one for the recording and monitoring of costs, one for production planning and one for sales control. The parts which are determined are displayed in a certain sequence which depends on the frequency of use and the degree of standardization of the respective part.
US 2001/0023376 A1 does not describe how the information about the parts which are determined or the sequence in which the parts are displayed is used to predict failure frequencies or down times.